Method for producing inorganic oxide particles

Abstract

The present invention relates to a method for producing inorganic oxide particles, comprising at least the following steps of: coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycodensation reaction of a metal alkoxide in the presence of a basic catalyst; filtering the dispersion to obtain particles; and drying the particles, wherein the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion. The inorganic oxide particles obtained by the method of the present invention have high purity and are excellent in flowability.

The invention claimed is: 
     
       1. Surface treated inorganic oxide particles having a crush strength of 0.01 to 0.06N, said surface treated inorganic oxide particles being produced by a method comprising:
 coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycondensation reaction of a metal alkoxide in the presence of a basic catalyst by using of a mixture of water and an alcohol as a solvent; 
 filtering the dispersion to obtain particles; and 
 drying the particles, wherein 
 the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion, 
 the step of coagulating the dispersion is carried out after the step of adding at least one surface treating agent selected from the group consisting of a silicone oil, a silane coupling agent and a silazane to the dispersion; and 
 the inorganic oxide particles to be produced are surface treated inorganic oxide particles having a crush strength of 0.01 to 0.06N. 
 
     
     
       2. The surface treated inorganic oxide particles according to  claim 1 , wherein, after a sieve having an opening of 355 μm, a sieve having an opening of 250 μm and a sieve having an opening of 150 μm (all the sieves have a diameter of 75 mm based on JIS Z8801) are placed one upon another at intervals of 2 cm in this order from the top, 5 g of the particles is put on the top sieve and vibrated vertically at an amplitude of 1 mm and a frequency of 60 Hz for 15 seconds, the agglomeration degree calculated from the amounts of particles remaining on these sieves based on the following equation is 60% or less; and
   wherein agglomeration degree(%)={(amount of remaining particles on top sieve+amount of remaining particles on middle sieve×0.6+amount of remaining particles on bottom sieve×0.2)}÷initial mass of surface treated inorganic oxide particles×100.
 
 
     
     
       3. The surface treated inorganic oxide particles having a crush strength of 0.01 to 0.06N according to  claim 1 , wherein the surface treatment of the inorganic oxide particles is carried out by further adding at least one surface treating agent selected from the group consisting of a silicone oil, a silane coupling agent and a silazane to the dried inorganic oxide particles after the drying step. 
     
     
       4. Surface treated inorganic oxide particles having a crush strength of 0.01 to 0.06N, said surface treated inorganic oxide particles being produced by a method comprising:
 coagulating a dispersion obtained by carrying out the hydrolysis reaction and the polycondensation reaction of a metal alkoxide in the presence of a basic catalyst by using of a mixture of water and an alcohol as a solvent; 
 filtering the dispersion to obtain particles; and 
 drying the particles, wherein 
 the step of coagulating the dispersion is carried out by adding a coagulant comprising at least one compound selected from the group consisting of carbon dioxide, ammonium carbonate, ammonium hydrogen carbonate and ammonium carbamate to the dispersion, 
 wherein surface treatment of the inorganic oxide particles is carried out by adding at least one surface treating agent selected from the group consisting of a silicone oil, a silane coupling agent and a silazane to the dried oxide particles after the drying step; and 
 the inorganic oxide particles to be produced are surface treated inorganic oxide particles having a crush strength of 0.01 to 0.06N.